Towards the implementation of the WRF-Chem model in Buenos Aires

CARRASCO, F.; PINEDA ROJAS A.L.; RUIZ, J.; BOGO, H.

Fort Collins

Congreso; 9th International Congress on Environmental Modelling and Software (iEMSs); 2018

Environmental Modelling and Software Society

The WRF-Chem model is implemented in the Metropolitan Area of Buenos Aires (MABA) for the first time. In order to determine the best model configuration representing transport and dispersion within the planetary boundary layer (PBL), several simulations are performed considering different PBL schemes (YSU, MYJ, QNSE, MYNN and MYNN3)and horizontal resolutions (1 km and 5 km). An analysis of its performance to simulate carbon monoxide (CO) concentrations at a green urban site and relevant atmospheric variables (air temperature, wind speed and direction) is presented. Four 5-day-periods are selected covering different seasons of the year. All simulations are performed in a 330 km x 305 km domain considering 38 vertical levels, the Noah Land Surface Model and the MODIS land use data. Meteorological initial and boundary conditions come from the Climate Forecast Reanalysis System. CO emissions belong to a high-resolution emission inventory developed for the MABA. The sensitivity of model results to the choice of the PBL scheme is studied considering a 5 km horizontal resolution. Atmospheric variables are well simulated by the five schemes. Statistical comparison between modelled and observed hourly CO concentrations shows that there is no single PBL scheme that performs best for all measures and seasons. MYNN, QNSE and YSU present better statistics in autumn, winter and spring, respectively. When horizontal resolution is increased to 1 km, no clear improvement is observed. The modelled CO peak concentration can be lower or greater than that obtained with the 5 km resolution simulation, highlighting the role of changes in variables other than emissions.